DINA

Via what means? Through the oil pan, or is it some obnoxious thing that's strapped to the top of the engine?

Thanks

wisconsin_quat

you've got the wrong mindset for the job

Mr. fix-it

More like an obnoxious thing bolted to the front of the engine.....

SiV6Qcoupe

I would be interested in why you suspect the oil pump to be faulty just out of curiosity as I have an oil pressure issue that is on-going despite replacing my oil pump, pressure valves and engine bearings, I suspect a fault with the suction tube going to the oil pump, perhaps a weak seal on the strainer moulding.

Anyway.. to change an oil pump on a V6 you're going to first remove the accessory belt followed by the timing belt. Then remove the crank bolt. Remove the lower oil sump pan after draining the oil. Remove M6 bolts on the front of the oil pump and those under the pump found by removing the sump pan also remove the timing belt roller pulley and a screw-in oil plug.

<img src="http://pictureposter.audiworld.com/18363/pumpopen.jpg.jpg"> Crank mounted pump rear view

You'll need timing belt tools, a large bar, a 10mm hex socket, large allen keys and a new sump and pump gasket.

wisconsin_quat

low or high pressure problem?

SiV6Qcoupe

Initial cold startups and 1 hour+ standing startups I get zero oil presssure. I have to spin the pump faster by giving it anywhere between 2k and 3.5k revs for it to suck oil up to the bearings. Once oil flows there is textbook oil pressure. Weird problem huh!

wisconsin_quat

Definately- what filter are you using and when is the last time you replaced it, also have you experimented with running different oil in the mean time while you fix your problem?? I'd probably use 20-50 or at least 10w-40

20VT90q

I thought you fixed the problem of crappy oil pressure? I can't beleive all the hoops you have had to go through to fix this problem. I hope you can fix this soon!

SiV6Qcoupe

I've used OEM filters and others even the large diesel type and all make no difference and they all contain anti-drainback valves as you would expect where the engine design has the filter horizontally mounted above the sump oil level.

Oils, i've used 10w40, 15w40, 10w40 semi-synth, 15w40 semi-synth, 10w40 Castrol Magnetec.
One thing I notice is when the engine oil is hot and the engine is shut down and restarted, say an hour later, it can be an absolute pig to bring the oil pressure/flow up due to the low viscosity of the oil especially semi-synth oil but once the pump voids get filled there is no problem.

I say i'm loosing oil from the pump via the suction tube so on startup I've got an air pocket to evacuate first before the pump draws oil up; to remove an air pocket takes a lot more pumping power (engine revs) than a viscous engine oil. The pump isn't leaking oil externally or anywhere else so I suspect an internal leak.

SiV6Qcoupe

Yeah, the problem is probably one of those one in a million occurances. I thought originally it was due to a worn oil pump where backlash between the gears had built up but even with a new pump the problem soon returned especially now the weather is warmer and the oil viscosity stays thinner for longer after turning the engine off.